Google searches show the DMCA takedown notices that list the sites that illegally stream content. It seems to me that if an interested party were to search for something on google and happened to see the DMCA take down notice, they might peruse that takedown request and see a number of sites that might illegally host such copyrighted content - so they know what sites to avoid of course.
Just checked, you’re right! When did they stop this and is there any report on why? I was seeing these up until just a few months ago.